Thanks for the post, Babs. My understanding is that many states don't require a listing of the chemicals, which is playing havoc with the environmentalists when it comes to proving contamination. Those states that do require a listing of the chemicals don't require specific percentages or concentrations, which also makes EPA folks cringe. But with chemicals being about 1% of the total solution used to extract gases, I suspect any contamination that is found comes from broken pipes or leaking hoses on the surface. The injection under pressure is so far below the water tables that it's a hard case to prove regarding contamination. Add to that the fact that the environmental laws don't "reach" that level below the water table as written.
At least deisel has been replaced in the process. Gotta admit that I never liked that in any percentage or combination.